Elsevier

Journal of Critical Care

Volume 22, Issue 4, December 2007, Pages 290-295
Journal of Critical Care

Interhospital transfer of critically ill patients: Demographic and outcomes comparison with nontransferred intensive care unit patients,☆☆

https://doi.org/10.1016/j.jcrc.2007.06.002Get rights and content

Abstract

Purpose

We examined the association between access to intensive care services and mortality in a cohort of critically ill patients.

Materials and Methods

We conducted an observational study involving 6298 consecutive admissions to the intensive care units (ICUs) of a tertiary care hospital. Data including demographics, admission source, and outcomes were collected on all patients. Admission source was classified as “transfer” for patients admitted to the ICU from other hospitals, “ER” for patients admitted from the emergency room, and “ward” for patients admitted from non-ICU inpatient wards.

Results

Transfer patients had higher crude ICU and hospital mortality rates compared with emergency room admissions (crude odds ratio [OR], 1.51; 95% confidence interval [CI], 1.32-1.75). After adjusting for age, sex, diagnosis, comorbidities, and acute physiology scores, the difference in ICU mortality remained significant (OR, 1.30; 95% CI, 1.09-1.56); however, hospital mortality did not (OR, 1.19; 95% CI, 1.00-1.41). Compared with ward patients, transfer from other hospitals was associated with lower hospital mortality after adjusting for severity of illness and other case-mix variables (OR, 0.81; 95% CI, 0.68-0.95).

Conclusions

We found some evidence to suggest that differential access to intensive care services impacts mortality within this case mix of patients. These findings may have implications for current efforts to centralize and regionalize critical care services.

Introduction

Critically ill patients presenting at smaller community or rural hospitals, where intensive care services are either not available or limited, are appropriately transferred to the intensive care units (ICUs) of tertiary care centers. Interest in the association between access to intensive care services and outcomes for critically ill patients has fuelled investigations examining the impact of transfer status (whether a patient was transferred from another hospital or not) on patient and hospital outcomes [1], [2], [3]. In addition to being sparse, available evidence examining outcomes for ICU transfer and nontransfer patients is also conflicting [1], [2], [3], [4], [5]. Investigations to date lack methodological rigor. In particular, small sample sizes [2], [5] and inadequate control for potential confounders [3], [6] limit inferences. To date, only 2 studies have used a validated severity-of-illness index for ICU patients to compare risk-adjusted outcomes for transferred and nontransferred patients [4], [7]. Evidence from several other patient populations, including surgical and internal medicine, suggests that compared with nontransferred patients, transferred patients have poorer outcomes, including higher mortality, morbidity, and costs [8], [9], [10].

Given current emphasis on hospital mergers and consolidation of specialized services within tertiary centers, the transportation of patients between hospitals will continue to be an established aspect of health care delivery systems, and it will be increasingly important to establish whether variations in access to intensive care services impact patient outcomes. The aim of the present article was to examine whether differences in hospital mortality exist between transfer and nontransfer patients admitted to a tertiary care center after adjusting for case mix and severity of illness.

Section snippets

Patient population

A retrospective cohort study was conducted in the 2 adult ICUs at the London Health Sciences Centre, a 787-bed tertiary care teaching hospital in Ontario, Canada. These units accounted for all ICU beds in the hospital, with 26 and 30 beds, respectively. As the only tertiary care teaching hospital in Southwestern Ontario, it is the primary ICU referral center for this region, with most referrals coming from community and rural hospitals within a 200-km radius. Although no standard retrieval

Results

The database contained 7067 patients whose admission source to the ICUs was the ER, general wards, or other hospitals. After exclusion of patients with missing APACHE II scores (109 [1.5%]) and readmitted patients (660 [9.3%]), 6298 (89.1%) patients were available for the analyses. Table 1 details the demographic and clinical characteristics of these patients. All patients had a medical admission diagnosis. However, the distribution of admission diagnoses varied, with the most common diagnosis

Discussion

Our findings demonstrated that there were important differences in mortality between ICU patients admitted from the hospital's general wards or ER and those transferred from other hospitals. We found that crude ICU and hospital mortality rates were significantly higher in transfer patients compared with patients admitted to the ICU from the ER. The difference in ICU mortality remained significant after adjusting for age, sex, APS, comorbidities, and admission diagnosis; however, hospital

Conclusion

On the basis of these results, it would appear that higher mortality may be limited to comparisons between transfer patients and patients admitted directly from the ER to the ICU. The implication is that differences in access to intensive care services may impact outcomes within this case mix of patients. Although patient transfers are inevitable in current health care systems, this practice should be prospectively monitored using data on the entire patient encounter. In particular, attention

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  • Cited by (0)

    Work for this study was performed at the London Health Sciences Centre, Ontario, Canada, and the University of Western Ontario.

    ☆☆

    Partial support was received from Physicians Services Incorporated Foundation.

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